 * {
     margin: 0;
     padding: 0;
     box-sizing: border-box;
     font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
 }

 body {
     display: flex;
     justify-content: center;
     align-items: center;
     min-height: 100vh;
     background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
     padding: 20px;
 }

 .container {
     display: flex;
     flex-wrap: wrap;
     justify-content: center;
     gap: 30px;
     max-width: 1200px;
 }

 .card {
     position: relative;
     width: 300px;
     height: 400px;
     perspective: 1000px;
     cursor: pointer;
 }

 .card-inner {
     position: relative;
     width: 100%;
     height: 100%;
     transition: transform 0.8s;
     transform-style: preserve-3d;
     box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
     border-radius: 15px;
 }

 .card:hover .card-inner {
     transform: rotateY(180deg);
 }

 .card-front,
 .card-back {
     position: absolute;
     width: 100%;
     height: 100%;
     backface-visibility: hidden;
     border-radius: 15px;
     overflow: hidden;
 }

 .card-front {
     background-color: white;
     display: flex;
     flex-direction: column;
     justify-content: flex-end;
 }

 .card-back {
     background: linear-gradient(135deg, #6a11cb 0%, #2575fc 100%);
     color: white;
     transform: rotateY(180deg);
     display: flex;
     flex-direction: column;
     justify-content: center;
     align-items: center;
     padding: 30px;
     text-align: center;
 }

 .card-image {
     width: 100%;
     height: 70%;
     background-size: cover;
     background-position: center;
 }

 .card-content {
     padding: 20px;
     height: 30%;
 }

 .card-title {
     font-size: 22px;
     font-weight: 600;
     margin-bottom: 10px;
     color: #333;
 }

 .card-description {
     font-size: 14px;
     color: #666;
     line-height: 1.5;
 }

 .card-back-title {
     font-size: 24px;
     margin-bottom: 15px;
 }

 .card-back-text {
     font-size: 16px;
     line-height: 1.6;
     margin-bottom: 20px;
 }

 .btn {
     display: inline-block;
     padding: 10px 25px;
     background: white;
     color: #6a11cb;
     border-radius: 30px;
     text-decoration: none;
     font-weight: 600;
     transition: all 0.3s ease;
     box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
 }

 .btn:hover {
     transform: translateY(-3px);
     box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
 }

 /* 卡片1样式 */
 .card:nth-child(1) .card-image {
     background: linear-gradient(45deg, #ff9a9e 0%, #fad0c4 100%);
 }

 .card:nth-child(1) .card-back {
     background: linear-gradient(135deg, #ff9a9e 0%, #fad0c4 100%);
 }

 /* 卡片2样式 */
 .card:nth-child(2) .card-image {
     background: linear-gradient(45deg, #a1c4fd 0%, #c2e9fb 100%);
 }

 .card:nth-child(2) .card-back {
     background: linear-gradient(135deg, #a1c4fd 0%, #c2e9fb 100%);
 }

 /* 卡片3样式 */
 .card:nth-child(3) .card-image {
     background: linear-gradient(45deg, #ffecd2 0%, #fcb69f 100%);
 }

 .card:nth-child(3) .card-back {
     background: linear-gradient(135deg, #ffecd2 0%, #fcb69f 100%);
 }

 /* 响应式设计 */
 @media (max-width: 768px) {
     .container {
         flex-direction: column;
         align-items: center;
     }

     .card {
         width: 100%;
         max-width: 350px;
     }
 }